What is the cornea?
The cornea is a transparent part of the eye that allows light to enter and performs two -thirds of focusing tasks. This part also covers both the iris, the color part of the outer eye and the pupil, the reactive "light meter" in front of the lens. There are no blood vessels in the cornea, but there are several nerves. The nutrients for this part are supplied by the same source as tear channels and internal through fluids. Indeed, the cornea allows you to enter the eyeball and its convex shape focuses on the light on the pupil and another structure called the lens. The cornea basically performs wide vision brushes, while the shape lens performs fine details before all light hits the retina. It is the shape of his dome, which determines whether one can be a short -sighted, far -sighted or astigmatic.
During visual correction procedures, external lenses can be modified to focus images in the eye lens or corneal shape. Contact lenses located directly on the cornea change its thickness and create a new focus. Some advanced contact lensesThe tension to transform the entire cornea, which allows almost normal vision until it renews its original shape and returns.
Advanced surgery, such as a lasik, make small cuts on the cornea, which should create a new degree of curvature during healing. Local anesthetics anesthetic nerves leading to the area and the procedure is practically bloodless. Occasionally, the cornea can be scratched with external objects or vicious algae under the lid. Removing residues can be a simple matter of using an approved eye drop, but it often takes a few days to recover the eye from scratches.
Some people can develop serious health conditions involving cornea, including corneal cancer and ulceration. Because it does not contain blood, tissue is remarkably resistant to rejection. This led to the development of corneal transplant operations. Many organ donors mention the cornea as one of their harvesting tissues after deathi. Unlike other organs and tissues, healthy tissue is almost always compatible with patients waiting for its acceptance.